1. Field of the Invention
The present invention is related with an information recording method and apparatus for adding and recording new record information subsequent to old record information recorded previously on a recordable information record medium, such as a high-density optical disc and the like, represented by DVD-R (DVD-Recordable) on which the information can be recorded only once.
2. Description of the Related Art
Generally, in the recordable information record medium on which the information can be recorded only once, when it is tried to later overwrite the new record information to an area on which the old record information has once been recorded, both the old record information and the new record information may be broken.
In the information recording method and apparatus for adding and recording the new record information to this kind of the recordable information record medium, when recording the new record information subsequent to the old record information, a linking area (or a boundary area) corresponding to an information amount of a single error correction unit, such as an ECC (Error Correcting Code) block and the like according to the error correcting system used therein, was conventionally provided at the linking or boundary portion of the old record information and the new record information. In the linking area, a meaningless dummy information or a predetermined RF (Radio Frequency) signal is recorded at a last portion of the old record information or a first portion of the new record information, and then the new record information is recorded thereon.
The reason why this linking portion is provided is as follows. If the linking portion is not provided, at the time of consecutively reproducing the new record information, recorded later, as well as the old record information, the RF signal may be discontinuous at the boundary of the record area of the old record information and the record area of the new record information, thereby resulting in an unstable focus servo or tracking servo control.
The reasons why the linking portion is provided for the data capacity corresponding to one ECC block is and why the meaningless dummy information or the like is recorded there in are explained below. In the conventional error correcting process, the error correction is performed by each error correction unit. If the new record information is recorded from the middle of the error correction unit, the appropriate error correction can not be performed for a head portion of the new record information, at the time of consecutively reproducing the old record information and the new record information later. Thus, the appropriately continuous reproduction can not be performed. In this regard, if the meaningless dummy information or the predetermined RF signal is recorded for one ECC block within the linking area as mentioned above, it is possible to reproduce the old record information and the new record information continuously by skipping the linking area and reproduce the new record information from an ECC block next to the linking portion, even though the overlapped portion of the old record information and the new record information in the linking portion is broken.
Further, another reason why the linking area is provided is as follows. If the new record information is recorded to follow the old record information without providing the linking area, both of the old record information and the new record information may be broken at the overlapped portion of them. In that case, if the information broken portion exceeds a single error correction unit, it is impossible to recover the broken record information. For the reasons described above, the linking area is provided at the linking or boundary portion of the old record data and the new record data.
However, the conventional error correction unit has relatively large capacity, for example, approximately 32K bytes, and this area is entirely filled with meaningless information having no relation with the recorded information. Therefore, there is a problem that it results in an extremely ineffective use of the high-density disk or the like, which needs to record a large amount of information.